Conventionally, a road condition management method for managing road conditions by allowing a manager, who manages conditions of road signs and road conditions such as holes in roads and fallen objects, to view an image (a captured image) acquired by imaging a road with an on-board camera is known.
However, in the conventional road condition management method, an engineer who can determine cracks in a pavement performs human work of visually checking the number of cracks in a captured image and calculating a crack ratio in a pavement analyzing process including calculation of a “crack ratio” which is an important evaluation index (Handbook of Pavement Inspection/Examination Methods (Japan Road Association)) for road surface properties of an asphalt-paved road. Accordingly, an amount of captured images which needs to be visually checked in an analysis process of cracks on a route with a long distance may be enormous and it may be difficult to achieve improvement in efficiency of the crack analyzing process.